This grant application proposes the development and the scientific and preclinical evaluation of an advanced, large field of view digital chest imager based on a 2048-channel Kinestatic Charge Detector (KCD). The detector will have 0.2 mm collector electrode spacing, giving 2.5 (3.0) cy/mm spatial resolution excluding (including) the effects of magnification, quantum detection efficiency of 0.90, detective quantum efficiency of 0.75 and will accept an x-ray beam thickness up to 1 cm. The detector parameters will be modeled and measured using test patterns and mechanical phantoms. A preclinical evaluation will be made using anthropomorphic phantoms and biological specimens. Finally, a preliminary clinical evaluation will be made on twelve volunteer patients, three each having the following pathology: interstitial lung disease and small pneumothoraces (requiring excellent spatial resolution), and metastatic disease and sarcoid adenopathy (requiring excellent contrast resolution). In addition, preliminary experiments will be undertaken on variations of this detector with 0.05-1.0 mm collector spacing giving spatial resolution up to 10(12) cy/mm excluding (including) magnification. Another variation of this detector will have split-collectors with 0.2 mm spacing for dual-energy digital chest imaging. The major impact on health care expected from this research derives from the ability of a KCD imager to provide simultaneously high spatial and contrast resolution, low patient dose and instant digital images.